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Old 04-11-2012, 06:58 PM
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Did I hurt my 12 bolt?

Sorry so long - here is my situation: 12 bolt from a 1970 Chevelle in a street rod with a Cad 472 that is slightly livelier than stock. I bought the car after it sat for 15 yrs. Rear was supposedly working well when put in car, but had leaky pinion seal when I got it last year so I thought seal replacement was in order.
I noticed pinion nut was not very tight when I removed it; maybe 100 pounds?. I installed new seal, new fluid, and closed it back up with about 150 ft lbs on nut. On the road I hear a slight whining; car has no glass and I never drove it before I replaced the seal so I don't really know how loud it is. Anywho, I soon notice the pinion seal I put in is leaking (I did not put sealer around the outide).
I take rear cover off and look around...smear some grease on ring gear to look at wear pattern, which looked fairly good to my untrained eyes. Put in new seal and torque nut to all I can get working under car; about 220 ft lbs. Spec, I believe is 255 ft lbs.
Now on the road, the noise appears to be louder. Still no glass in car so I pretend noise is not there and drive car intermittently for about 100 miles trying to break in rebuilt motor.
Now that I have concluded the noise is real, and I would like to fix it, I read up and it appears my torquing of the pinion nut may have crushed the seal more and be the cause of my noise? BTW...the noise is almost not present driving under no load, gets louder as the load gets larger, and goes away coasting down a hill. The noise is a steady medium pitch whine.
I need some guidance to direct me, please.
1) Does the sound I am hearing sound like it could be caused by my torquing the pinion nut up around 220? I do not understand this, but that is what I thought I read on some old posts.
2) What is the fix?
3) I read about crush sleeves and crush sleeve replacement sleeves. I contacted Mark Williams Co and they no longer sell crush sleeves and state that GM no longer makes them. They sell their non-crush replacement instead, but it does not use shims so has to be machined to get proper preload. Ratech has their version with shims. Is this a better option than the factory crush sleeve, keeping in mind that I can't seem to get over 220 ft lbs on the pinion nut in my current working conditions?
4) How big of a job is the replacement? I have never worked with a rear-end, but am willing to try. Is there a good tutorial on the web?
5) Is it likely in the 100 easy miles that I could have damaged more components?

All advice is always appreciated.


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Old 04-12-2012, 08:00 AM
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I doubt you hurt any big parts.

Take the whole thing apart and replace the pinion bearings and use the Ratech spacer. Reuse the existing pinion shim. I like the crush sleeves cause they work good and are quick and easy for me to install, but you have to torque the snot out of the nut to crush them. The solid spacers take some time to find the exact right shim, but it works well. Use a new locknut and red loctite on the nut when going for final torque.
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Old 04-13-2012, 07:10 PM
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Thanks for the reply Imsport.

1) Does the noise I have sound consistent with the issue I think I have?
2) I have not ever worked with a rear end, and do not understand how replacing a leaky oil seal and torquing the pinion nut to proper lbs would over-crush the sleeve and cause bad tolerances. Is this correct, and how?
3) I am a bit leery of trying this job myself. I have worked on all aspects of this car, but the thought of trying to do this job by myself while lying on my back just does not sound good. How much should I expect to pay a professional to do it?

Any advice is appreciated.

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Old 04-16-2012, 08:56 AM
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Here a little trick my dad showed me on rear end setup. He said back in the day no one had Dial gauges and the like to set up a rear end gear set so they would take a farmer match put a little grease on it lay it in the gears and roll the gears over it. He said it should smash the wood match flat but not cut through it. Used it at the race track to put some gears in one weekend it worked. The next week after we got back from racing we went through the rear. Set it up the way you should and put a match in to test his old-timers method and it came out just like he said it would.
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